A Scintigraphy or (otherwise known as) Radionuclide Scan is commonly called nuclear medicine. It’s painless and helps with diagnosis for a wide range of conditions.  Nuclear medicine uses a tracer dye, which is mildly radioactive, but is considered very safe. The radioactivity is about the same as an x-ray, and it dissipates within a few days.  These scans are considered to be very safe and painless.